Piston for reciprocating engines



F. H. ROYCE.

PISTON FOR RECIPROCATING ENGINES..

APPLICATION FILED DEC-I3, I920.

Patented .Im 17, 1922. l

A UNITED STAT-Es PATENr OFFICE;

FREDERICK HENRY ROYCE, or DERBY, ENGLAND, AssIoNon To ROLLS-ROYCE LIMITED, or DERBY, ENGLAND.

PISTON FOR RECIPROCATING ENGINES.

Specification of Letters Patent. Patented Jan. 17, 1922.

Application led December-13, 1920. Serial No. 430,344.

, of which the following is a specification.

This invention relates to pistons of the trunk type, that is to say, those "in which the duty of the piston proper is "combined with that of a cross-head, the walls of the cylinder acting as the cross-head g ide.

In connection with such pistons/there is a tendency, owing to the angularity of the connecting rod, for the piston to be thrown (generally on the power stroke) to one side of the cylinder and this causes an' audible noise generally known as a knocking and whilst many devices have been resorted to in order to obviate this knocking, the present invention comprises a novel o r imroved means for obviating same, as hereinafter fully describe'd and specifically pointed out in the appended claims.

An embodiment of the invention is illustrat-ed in the accompanying drawings, wherein Fig. l is a side elevation of an improved 'iston, Fig. 2 is a vertical central section t ereof, and Figs. 3 and 4 are horizontal sections on the lines 3--3 and Llr-l respectively of Fig. 2.

rThe skirt a. of the piston b is divided vertically into two parts b1 o2 from the bot- 1 tom upwards for nearly the whole tf its height by means of a split or cutawa part c. One of such parts b1 is rigid and) contains the pin d of the connecting rod il and constitutes the main part of the skirt a. The other part b2 is flexible andis subjected to the action of a Spring and stop hereinafter referred to. The part b2 constitutes a comparatively small part of said piston skirt. and is most remote from the side of the piston which is thrown against the cylinder wall on the power stroke.

lWithin the skirt are fixed by means of. bolts c1 and nuts e3y a steel or other suitable.

spring e, preferably of the sugar tongs type, which forces the tlexible part b2 of the' skirt outward, and an adjustable stop in the form of heads e2 on the bolts e1 which limits thef` extremo outward position of the part o2.

The spring e exerts a force suiiicient, but

not more than sufficient', to ensure that the flexible part b2 of the skirt will not bedisplaced by the angular force exert-ed on the piston during the compression stroke.

By means of this arrangement, the stop constituted by the bolts el and heads c2 can be adjusted so that the flexible part b2 will exert pressure on Athe wall of the cylinder suiiicient to hold the piston constantly in contact with the wall on the other side and at the same time avoid any undue friction on the wall by reason of the action of the' spring, and further, if it should happen that the skirt should expand beyond the minimum clearance allowed, owing Ato its coefficient of expansion under heat being greater than that of the metal of the vcylinder' or owing to the faulty adjustmentof the stop or for any other reason, the flexible part will yield, whereby no seizure will take placey and the abnormal friction will be limitd by the eii'ective power of the spring, which is predetermined as above explaine Th* invention is also applicable to slipper pistons, such as the Ricardo type.

Wl atl claim as my invention and desire to sel-,ure by Letters Patent of the United States is 1. A piston for reciprocating engines divided longitudinally by means of a split or cut-away portion into a relatively-large, rigid member and a relatively-small, flexible member, and a spring acting on the iiexible member for automatically forcing it outwardly of the piston.

2. A piston for reciprocating engines divided longitudinally into two cdnnected members by means of a split or eht-away portion, one of said members being rigid and the other flexible, a spring acting on the flexible member for forcing it oubwards, and means for limiting the outward movement ot said flexible member.

3.. A piston for reciprocating engines divided longitudinally by means of a split or cut-away' portion into a relatively-large,

rigid member and a relatively-small, flexible member,a` spring acting on the flexible member foi-'automatically forcing it outwardly of the piston, and adjustable means for limiting the outward movement of said flexible member:

4. A piston for reciprocating engines hav,-

ing a skirt portion formed with a flexibleV member producel by longtdiually slitting specification in the presence of 'two wi snid'skirt, a spring secured Within the skirt nesses.

and adapted t0 exert Outward pressure on 1 y ,s said `exible member, and adjustable abut- FREDERICIX HENRY ROYJF ment means for lmitinv the outward thrust Witnesses:

of sadspring or'fexibfe member. H. R. CUTTEN,

. In witness' whereofl I have signedrths F. PARSONS. 

